the 26 children and teachers gunned down at the sandy hook elementary school almost six weeks ago. and these are the guns they want to get off the streets. the legislation unveiled today marks the first major test of whether the newtown, connecticut, massacre was indeed a turning point in the national debate over gun control. let's bring in our chief congressional correspondent, dana bash. dana, one senator in particular is on a personal mission to get this measure passed. >> reporter: that's right. of all of the gun control items that president obama proposed last month, earlier this month, i should say, this is going to be the toughest to pass through congress, reviving the assault weapons ban, which expired about a decade ago, almost. but it is because this particular senator is on a personal mission, based on a tragedy that happened four decades ago. for dianne feinstein, it's personal. >> i became mayor as a product of assassination. >> both mayor moscone and supervisor harvey milk have been shot and killed. >> reporter: the death of her colleagues, including harvey milk, the